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(No Model.)

H. W. JOHNS.

NON-CONDUCTING GOVERIN'G.

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i UNITED STATES PATENT OFFICE.

HENRY W. JOHNS, OF NEIV YORK, NQY.

NON-CONDUCTING COVERING.

SPECIFICATION forming part of Letters Patent No. 433,472, dated August5, 1890.

Application tiled February 12, 1890. Serial No. 340,165. (No model.)

To all whom it may concern:

Be it known that I, HENRY IM. JOHNS, a citizen of the United States, anda resident of New York city, in the county of New York and State of NewYork, have invented certain new and useful Improvements in Non-Conducting Coverings, of which the following is a specification.

My invention relates to a new and useful non-conducting covering forpipes, boilers, and other heated surfaces; and it consists in making thecovering from successive layers of soft, compressible, andexceedingly-porous sheets or slabs of wood pulp, which are to beiireproofed and preferably waterproofed.

In the drawings, Figure l illustrates one form of my invention, in whichI show a section of pipe-covering formed of a plurality of layers ofreproofed wood pulp. Fig. 2 illustrates the same as shown in Fig. l,there be- 4ing also present an interlayer of asbestus or otherfire-proof sheet or cement. Fig. 3 illustrates a pipe-covering inprocess of ceiling. Figs. ft and 5 illustrate corrugated and indentedsheets or slabs.

In making` my improved covering I first form the wood pulp into sheetsor slabs A, of such thickness as may be preferred, by a felting orpulping process, whereby I secure a product possessing great porosityand softness. This sheet is then subjected to a treatment in anypreferred manner with iireproofing materials, preferably in liquid form,and preferably using' the ireproofing compound of borax and boracicacid, with or without zinc, for which I applied for Letters Patent ofthe United States January 7, 1890, the said application being Serial.No. 336,196. Then the sheet has been moistened by its absorption of theliquid iireproofing material, it may be easily rolled into cylindricalforms upon a suitable mandrel of substantially the diameter of the pipeto which the covering is to be applied, and when dry it may be sawed orcut into halves foreasy application to the pipes; or instead of firstmaliin g the sheets or slabs and then treating them with the fireprooingliquid, they may be treated therewith While yet in the plastic state,and then before the sheets have dried they may be rolled or otherwiseformed into cylindrical or other desired shape.

In Fig. 2 I illustrate a covering the same as that shown in Fig. 1,excepting that there is applied to the sheet A, before it is rolled intocylindrical form or otherwise shaped, a sheet, layer, or coating B oflire-proof substance, which Will be rolled up with the sheet, thusforming an interlayer or alternate layer with it in the completedcovering. I prefer to use a sheet of asbestus paper or a layer ofasbestus cement for this interlayer B; but any other suitable re-proofor practically fireproof material may be used instead. Ialso prefer,especially if the interlining sheet B is not used, to line the interioror surface of the covering with a layer or sheet O of pure asbestus whenthe covering is to be used on very hot surfaces.

In Fig. 3 I illustrate a sheet of the fireproofed pulp with interlayeras seen after having been rolled up on a mandrel. I also sometimes treatmy sheets or slabs either be' fore they are formed into the desiredshape4 or afterward, as preferred, with any suitable waterproofingmaterial, and this treatment may extend throughout all the layersforming the covering or be applied to certain ones only.

My covering, as I believe, possesses certain advantages over any otherknown. It is very light in weight, quite smooth in exterior surface,very inexpensive, very easy to manufacture and apply, very clean, and itpossesses innumerable air-spaces, partly in the body of the material andpartly in the spaces between contiguous sheets, which render it asuperior non-conductor- Moreover, my coverings, being composed of woodpulp, are When ydry (in which form I prefer to treat them with theiireproofng compound) more easily, economically, and thoroughlyimpregnated with the fireproofing liquid than any other materialsuitable for the purpose.

The exterior of my covering may be covered with canvas, paper, or suchother exterior jacket or binder as may be preferred, and it maybedecorated with paint or other suitable substance.

I illustrate' my coverings as made into cylindrical forms only 5 butthey may be flat or IOO of such other shape as desirable to iit thesurface to be protected, in which event the sheets with or Without aninterlayer will be cut into smaller sheets and superposed one upon theother.

The separate sheetsor slabs maybe indented or corrugated, as shown inFigs. 4 and 5, or the interlayer or interlayers maybe indented orcorrugated to increase the number of aircells. The several sheets,layers, or coils ot' the same sheet or the ends thereof may be confinedin place by any suitable adhesive material or by metallic bands,staples, or rivets,I or by sewing, nailing, or otherwise.

I claimm 1. A nonconducting covering composed, essentially, ofsuperposed layers of soft porous Wood pulp Iireproofed, substantially asset forth.

2. A non-conducting covering composed, essentially, of superposed layersof soft porous Wood pulp ireproofed, and an interlayer or interlayers ofpractically fire-proof material, substantially as set forth.

3. Anon-conducting covering composed, essentially, of superposed layersof soft porous Wood pulp reproofed, and an interior lining of nre-proofmaterial, substantially as set forth.

Signed at Nen*7 York, in the county of New York and State of Newsr York,this 29th day of January, A. D. 1890.

HENRY W. JOHNS.

Nitnessesz PHILLIPS ABBOTT, JOHN W. I-IIGHFIELDT.

